Such automatic biochemical analyzers for analyzing biological samples have been known, as proposed in Japanese Patent Laid-Open No. 2024/1993. In this prior art technique, a plurality of sample containers are set on a sample disk. In this instrument, aliquots of sample in the sample containers set on the sample disk are drawn in by a sample pipette and dispensed into reaction containers on a reaction disk. A reagent pipette draws in reagents from plural reagent disks and adds the reagents to the aliquots of sample. Thus, the sample is analyzed in terms of plural items. During the analysis, the order in which the items are analyzed is determined, taking account of the time required for the processing, in order to shorten this processing time.
In this automatic biochemical analyzer, a biological sample is reacted with plural reagents within reaction containers on the reaction turntable, and the reaction products are detected by detectors. Upon completion of the detection, each reaction container is sent to a washing location at which the container is washed by a washing device.
This washing operation starts with discharging the biological sample and the reagents from the reaction container. Then, the interior of the reaction container is washed a few times or several times with an alkaline detergent, an acidic detergent, or pure water. Finally, the interior of the reaction container is washed with pure water. The wash water is drained off, thus completing the washing of the reaction container. This washed reaction container is reused for measurement of the next biological sample unless the container is heavily contaminated.
The final stage of washing with pure water has been heretofore done by a washing device as shown in FIG. 6. This washing device comprises a relatively thin draining tube 24 and a thin-walled sucking portion 25 in the form of a block. The sucking portion 25 is mounted at the front end of the draining tube 24. An X-shaped groove 25a is formed in the bottom surface of the sucking portion 25. This groove 25a is in communication with the hole inside the draining tube 24.
In the operation of this conventional washing device, the sucking portion 25 is put into a reaction container 11 and made to abut against the inner bottom of the reaction container 11 or kept slightly afloat. When a draining pump (not shown) draws in fluid through the draining tube 24, the wash water in the reaction container 11 is drawn in from the sucking portion 25 and discharged into a draining tank (not shown) via the draining tube 24. When the wash water in the reaction container 11 is almost fully drained away, some droplets of the wash water may remain and adhere to the inner bottom and inner side wall of the reaction container 11. In this case, if next biological sample and reagents are injected into this reaction container 11, these biological sample and reagents might be affected by the remaining water droplets.
Accordingly, if the operator subsequently attempts to remove the remaining water droplets completely by the drawing action of the sucking portion 25, the water droplets adhering to the inner bottom of the reaction container 11 are attracted but the water droplets adhering to the inner side wall are hardly attracted. Therefore, it is quite difficult for the prior art washing device to remove water droplets adhering to the inner side wall of the reaction container.